OPTICAL DISK APPARATUS AND DISK ROTATION SPEED CONTROL METHOD THEREOF

• US 20080082994A1
• Filed: 03/13/2007
• Published: 04/03/2008
• Est. Priority Date: 10/02/2006
• Status: Active Grant

• Current Assignee: Hitachi-Lg Data Storage Incorporated (Hitachi, Ltd.)
• Original Assignee: Hitachi-Lg Data Storage Incorporated (Hitachi, Ltd.)
• Inventors: ITO, MASAMICHI, Minoda, Hiroshi
• Granted Patent: US 7,760,599 B2
• Time in Patent Office: Days
• US Class Current: 720/695
• CPC Class Codes: G11B 17/34 Guiding record carriers during transducing operation, e.g. for track following G11B17/32 takes precedence
• CPC Class Codes: G11B 19/24 Arrangements for providing constant relative speed between record carrier and head
• CPC Class Codes: G11B 7/0053 Reproducing non-user data, e.g. wobbled address, prepits, BCA

Abstract

In an optical disk apparatus and a disk rotation speed control method thereof, enabling to rotate a disk at high speed, with stability and certainty, irrespective of mass eccentricity thereof, detection is made on the greatest value and the smallest value on the signal after conducting a process of a band pass filter 511 on a lens error signal in a step response of a pickup, with using a wobble signal in the place of a tracking error signal and chaining an offset, when controlling the rotation speed of the apparatus by loading an optical disk therein, and thereafter, determination is made on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of the maximum value (Max_spnup) and the minimum value (Min_spnup) obtained with the greatest value (Max_step) and said smallest value (Min_step) memorized, when shifting the disk rotation to the high speed.

X=(Max_—spnup−Min_—spnup)/(Max_step−Min_step)

Claims

1. An optical disk apparatus, comprising:

a spindle motor to mount an optical disk thereon, for rotational driving thereof;

a pickup movable into a radial direction of the optical disk being rotationally driven by said spindle motor;

a rotation speed control means for controlling a rotation speed of said spindle motor; and

a pickup movement controller means for controlling movement of said pickup, thereby recording/reproducing information through irradiating a laser beam upon an information recording surface of the optical disk, further comprising;

a signal generator portion for generating at least a tracking error signal and a lens shift indication signal upon reflected light of the laser beam irradiated from said pickup; and

a signal process portion for controlling said rotation speed control means and said pickup movement controller means, upon basis of the tracking error signal and the lens shift indication signal from said signal generator portion, wherein

said signal process portion comprises a mass eccentricity detection mode, detecting a greatest value and a smallest value on a signal after conducting a band pass filter process upon said lens shift indication signal in a step response of said pickup, to be memorized, with using a predetermined high-frequency signal, in place of said tracking error signal, and by changing an offset thereof, when controlling the rotation speed after loading the optical disk into said apparatus, and thereafter,

detecting a maximum value and a minimum value on a signal after conducting band pass filter process upon said lens shift indication signal obtained from said signal generator portion, when shifting the disk rotation speed to a high speed, and thereby

determining on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of said maximum value and said minimum value obtained with said greatest value and said smallest value memorized.

2. The optical disk apparatus, as described in the claim 1, wherein said signal process portion has means for memorizing the greatest value and the smallest value to be memorized.

3. The optical disk apparatus, as described in the claim 1, wherein the predetermined high-frequency signal to be used in the place of said tracking error signal is a wobble signal.

4. The optical disk apparatus, as described in the claim 1, wherein the value obtained through comparison of said maximum value (Max_spnup) and said minimum value (Min_spnup) obtained to said greatest value (Max_step) and said smallest value (Min_step) memorized is expressed by the following equation:

X=(Max_—

spnup−

Min_—

spnup)/(Max_step−

Min_step)

5. The optical disk apparatus, as described in the claim 1, wherein said signal process portion shifts into a tracking control mode after completing said mass eccentricity detection mode.

6. The optical disk apparatus, as described in the claim 1, wherein said lens shift indication signal is the lens error signal.

7. A disk rotation speed control method in an optical disk apparatus, comprising:

a spindle motor to mount an optical disk thereon, for rotational driving thereof;

a pickup movable into a radial direction of the optical disk being rotationally driven by said spindle motor;

a rotation speed control means for controlling a rotation speed of said spindle motor; and

a pickup movement controller means for controlling movement of said pickup, thereby recording/reproducing information through irradiating a laser beam upon an information recording surface of the optical disk, comprising the following steps of;

a step for detecting a greatest value and a smallest value on a signal after conduction a band pass filter process upon said lens shift indication signal in a step response of said pickup, to be memorized, with using a predetermined high-frequency signal, in place of said tracking error signal, and by changing an offset thereof, when controlling the rotation speed after loading the optical disk into said apparatus, thereafter;

a step for detecting a maximum value and a minimum value on a signal after conducting band pass filter process upon said lens shift indication signal obtained from said signal generator portion, when shifting the disk rotation speed to a high speed, and

a step for determining on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of said maximum value and said minimum value obtained with said greatest value and said smallest value memorized.

8. The disk rotation speed control method of an optical disk apparatus, as described in the claim 7, wherein renewal is made through detecting the maximum value and the minimum value of the signal obtained while conducting the bandpass filter process on said lens shift indication signal, occasionally.

9. The disk rotation speed control method of an optical disk apparatus, as described in the claim 7, wherein the predetermined high-frequency signal to be used in the place of said tracking error signal is a wobble signal.

10. The disk rotation speed control method of an optical disk apparatus, as described in the claim 7, wherein the value obtained through comparison of said maximum value (Max_spnup) and said minimum value (Min_spnup) obtained to said greatest value (Max_step) and said smallest value (Min _step) memorized is expressed by the following equation:

X=(Max_—

spnup−

Min_—

spnup)/(Max_step−

Min_step)

11. The disk rotation speed control method of an optical disk apparatus, as described in the claim 7, wherein said signal process portion shifts into a tracking control mode after completing said mass eccentricity detection mode.

12. The disk rotation speed control method of an optical disk apparatus, as described in the claim 7, wherein said lens shift indication signal is the lens error signal.